Efficacy and safety of mixed amphetamine salts extended release (Adderall XR) in the management of attention-deficit/hyperactivity disorder in adolescent patients: a 4-week, randomized, double-blind, placebo-controlled, parallel-group study.

BACKGROUND

The ability to recognize and diagnose attention-deficit/hyperactivity disorder (ADHD) has increased in recent years. The persistence of ADHD symptoms puts adolescents with ADHD at risk for long-term adverse psychosocial outcomes.

OBJECTIVE

The primary goal of this study was to assess the efficacy and safety of mixed amphetamine salts extended release (MAS XR) in the management of adolescents with ADHD.

METHODS

This was a 4-week, randomized, multicenter, double-blind, placebo-controlled, parallel-group, forced-dose-titration study. Adolescents aged 13 to 17 years with ADHD were randomized to 1 of 4 active treatments (MAS XR 10, 20, 30 or 40 mg/d) or to placebo. All doses were given in the morning. This study used a forced-dose-titration design in which patients randomized to the 10-mg/d group received 1 dose of 10 mg/d for 4 weeks. Patients randomized to the 20-mg/d group received 1 dose of 10 mg/d for the first week and 1 dose of 20 mg/d for the remaining weeks; patients randomized to the 30-mg/d group received 1 dose of 10 mg/d for the first week, 1 dose of 20 mg/d for the second week, and 1 dose of 30 mg/d for the remaining 2 weeks; and patients randomized to the 40-mg/d group received 1 dose of 10 mg/d for the first week, 1 dose of 20 mg/d for the second week, 1 dose of 30 mg/d for the third week, and 1 dose of 40 mg/d for the fourth week. The primary efficacy measure was change from baseline to end point in the ADHD Rating Scale-IV (ADHD-RS-IV) score. The secondary efficacy measure was the score on the Clinical Global Impressions-Improvement (CGI-I) scale for ADHD. ADHD-RS-IV total scores were analyzed post hoc in patients with low baseline ADHD-RS-IV severity (ie, patients with baseline ADHD-RS-IV total scores less than the median) and high baseline ADHD-RS-IV severity (ie, patients with baseline ADHD-RS-IV total scores greater than the median). Safety was assessed by recording adverse events, vital signs, and body weight at all study visits and 30 days after drug discontinuation.

RESULTS

Of the 287 randomized adolescents, 258 completed the study. The intent-to-treat (ITT) population included 278 patients. The majority of patients were male (65.5%) and white (73.7%) The mean weight (57.8 kg [127.1 lb]) at baseline and the mean height (163.8 cm [64.5 in]) at screening were comparable across all MAS XR treatment groups. Patients in the placebo group had a mean weight of 59.8 kg (131.6 lb) and a mean height of 166.1 cm (65.4 in). Most (56.5%) of the patients had ADHD combined inattentive/hyperactive-impulsive subtype. Two hundred nineteen (78.8%) patients were treatment naive, and 59 (21.2%) had received treatment for ADHD within 30 days before screening. ITT analysis of the ADHD-RS-IV revealed statistically significant (P < 0.001) improvement in mean ADHD-RS-IV total scores in all 4 MAS XR treatment groups, compared with placebo, at all weeks throughout the 4-week study; the mean change from baseline to end point was -17.8 in the MAS XR 10- to 40-mg/d groups and -9.4 in the placebo group. Significant treatment effects were observed in both the ADHD-RS-IV inattentive (P < 0.001) and hyperactive-impulsive (P < 0.001) subscales from baseline. In patients with low baseline ADHD-RS-IV severity, statistically significantly (P < or = 0.01) greater improvements were observed in the MAS XR 20-, 30-, and 40-mg/d groups than in the placebo group; in patients with high baseline ADHD-RS-IV severity, statistically significantly (P < or = 0.02) greater improvements were observed in all active treatment groups compared with placebo. On the CGI-I scale at end point, a higher percentage of adolescents in all MAS XR treatment groups were considered improved (MAS XR 10 mg/d, 51.9% [P < 0.01]; 20 mg/d, 66.0% [P < 0.001]; 30 mg/d, 70.7% [P < 0.001]; 40 mg/d, 63.9% [P < 0.001]) compared with adolescents receiving placebo (26.9%). The most common adverse events in patients receiving MAS XR versus placebo were anorexia/decreased appetite (35.6% vs 1.9%), headache (16.3% vs 22.2%), insomnia (12.0% vs 3.7%), abdominal pain (10.7% vs 1.9%), and weight loss (9.4% vs 0%). Most adverse events were mild or moderate in intensity (97.5%); no serious adverse events were reported.

CONCLUSIONS

The adolescents with ADHD treated with 10- to 40-mg/d MAS XR up to 4 weeks had significant improvements in ADHD symptoms compared with those who received placebo. Results of this study suggest that once-daily dosing with MAS XR up to 40 mg was effective and well tolerated for the management of ADHD in these adolescents.